Worth going for a Mk.3.5 over a Mk.3? (and other questions)

Buying a ‘5 and Insurance advice Buying Advice
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Dear all

Just to let you know briefly my position…

I have lived in southern Spain for the last 17 years. I decide a couple of years ago to stick a bit aside each month with the view of buying a convertible. I started with the idea of buying an MR2 (yes, I know!) and after nearly 3 years I now have quite a bit more than I was planning to spend Smile. So I’ve narrowed it down to either an MX-5 or a Z4 (sorry). The thing that puts me off an MX-5 is the number of reports I read concerning rust problems, even on rather new models. I don’t want to buy a MX-5, bring it all the way down here then see it fall apart thanks to rust! But, having said that, I’m still swinging toward the MX-5 as it should be cheaper to import and also to run.

So, first of all, can I ask what the differences are between the Mk.3.5 and the Mk.3? I’ve seen a 2009 Mk.3.5 at a very good price so I’m tempted to ask for more details. I’ve Googled about the differences and a few say it’s better ‘aligned’ from the factory (?). Apart from that I can’t see too much of a difference to be honest.

Also, I’m not sure between the 1.8 & 2.0 engine. I’ve read a few say that the 1.8 is more reliable. Is that true? (the Mk.3.5 model I’m interested in is a 2.0 SE) I also much prefer the look of the MX-5 after it’s been lowered - I see ‘Wheels in Motion’ do a very good job with the Mazdas…

Well, I think that’s all for now. I’m sure I’ll be asking loads more questions in the near future. Must say, I’m dying to drive a rag-top in these parts! 

Thanks a lot in advance,

Nathan

 

 

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The Mk3.5 had shift improvements to the gearbox and some improvements to the engine for better reliability basically Mazda learned some things and made changes to improve reliability.

The Mk3.5 has an onboard computer that the Mk3 did not have so lots of little other improvements that you would expect after 3 or 4 years of production but no great game changers.

So it would be better to get a 3.5 IMHO if the price is right.

Both engines are very nice but why not get the 2 ltr if you are not strapped for cash.

I must say we like our Mk3 so just go for it .

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Modified front uprights where the lower ball joints mount lowered the roll centre on the facelift (Mk 3.5) car also.

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The question, is it worth? depends how much money you want to spend. At the present time a good low mileage mk3 with service history would cost between £6000-£7000. Whilst a mk3.5 in the same condition I suspect would be  £9000-£18000 depending on the model. 

I like the mk 3.5, this version had a number of tweeks. I believe the 3.5 is about 10-15mm lower than the mk3 thus giving a more sporty and driver responsive ride so there really is no need to lower it further, which mk3 cars seem to require. Also the Bose audio system was updated, seat height adjustment is good if you are small like me. The seats are more supportive too as well as a reworked arm rest/cubby box and its more full efficient and some have cruise control.

If you were to ask me if this car is worth £18000 I would have to say yes, but ask if i can afford one the my answer is no.

So I drive a mk3 and enjoy every moment of it, I can always mod my car, lower it, upgrade the audio, add cruise control, ect the list is endless and thats just as much fun as driving it!

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I have a 3.5 the ball joints did lower it a smidge more, although I am still looking to get mine lowered.

I find the 1.8 fine for driving and never really felt the need to consider the 2.0. Although underneath both engines are highly similar using the same overall block (hence why the engines look visually almost the same) so make sure any seller is aware whether it is a 1.8 or 2.0.

Regarding rust its true, but care for it well by getting the cavities and exposed parts all undersealed and just having a general check up now and again can really help prolong the car. The major rust points with the MK3 model (including 3.5 and 3.75) cover virtually the same issues with limited underbody protection and rear arches with the liner rubbing as well as the exposed metal fold are a major rust point, another one is the spot welds that when the boot is closed are still exposed to the elements and tend to show some bubbling.

Ultimately I have had mine for a year I came from a Volvo where rust was none existent and therefore had a steep learning curve in that respect. Question is would I go back? Unlikely, the issues with the MX5 disappear and are forgotten about as soon as I turn the key, and the MX5 also has that ability (unusual in these times) to actually be somewhat worked on. (Yes I am from an IT world but sometimes working on something without using a computer so much is a lovely bonus!).

 

 

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Nathan, I had a Z4 for 3 months and ended up getting my money back!! In short, poor reliability,ride and handling. The MX5 is 10 times the car, great handling and reliability and most of all a lot of fun!

Keep us updated on your decision.

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Hi Nathan, 

I switched from a mk3 (2007 model) to a mk3.5 (2009 model) in October last year. Both were Sport spec, so 2.0L with 6 speed manual. The mk3 had 30K when I bought it and put another 16K in a bit less than a year. I got the mk3.5 with 23K on the clock. 

The mk3.5 is just a more refined car. Is not that the mk3 is worse or that there is a night and day difference between them, far from it. But there are several tiny revisions on the mk3.5 that makes it a better package. And given that the price difference between them is just couple grands the mk3.5 gets more attractive. Here’s why:

  • Gearbox revision - other then tweaking a bit the synchros for the lower gears, the 6th gear on the mk3.5 is longer. And this is really nice for cursing. Mine turns around 3000 rpm when doing 70mph. With the older gearbox you where most of the time over 3500 rpm on the motorway. And on the continent you go a bit faster, between 75-80mph, so having a longer gear is really really nice. You’ll be just under 3500 rpm doing 80mph. The gearbox still benefits from an oil change, so do that if you go for a 3-4 years old model.
  • Engine upgrades - some of the engine internals are forged and a bit lighter. Other than the raised rev limit, on the 2.0L, the engine in the mk3.5 is(feels) stronger. And it really pulls a bit harder. The lighter internals help, but the engine maps are also tweaked. I drove both engines stock and with catless (4-1) manifold and tune and I must say that the stock mk3.5 fells near as good as a remapped mk3. A remapped mk3.5 is a peach, but that is another story. And shifting at 7300-7400 rpm on the mk3.5 is so addictive. Mk3.5 engine for me please...
  • Suspension revision. As mention in the previous posts, the front uprights where modified, changing the front roll centre but also lowering the front ride height a bit. But this is not the only change. On the sport model, the Bilstein dampers were tuned and they have better damping. The springs were also altered slightly. The ride hight didn’t change much, so people will still complain about the 4x4 look, but the mk3.5 rides better on the sport suspension than the mk3. I would not lower a mk3.5 in the beginning, they do ride nice stock. If you don’t like the roll try some stiffer antiroll bars. The biggest benefit of lowering the car is plain looks, but we are diverging again... You will still benefit from a 4 wheel alignment at a garage that understands how the mk3/3.5 suspension works. They are not ‘precision aligned’ from the factory - that’s why manufacturers are using the marked bolts and that’s why the alignment specs are so wide.
  • The interior and styling is subjective. But the centre console trim on the mk3.5 solves the pointless centre console storage from the mk3 (which is not cheap to change). I like the seats in the mk3.5 a bit more too. 
The above comments are for the Sport version. I never drove a 1.8L engine, and probably is a nice engine, but since I drive my  car quite hard and I would like even more power from the 2.0, I doubt I would be happy with the 1.8L. And as far as I know the 1.8 engine is the same between the mk3 and mk3.5 (same for the 5 speed transmission), so that make these two generations closer in this spec - only stye differences for the 1.8l based models. Also, the Sport model has quite some extras than the 5 speed 2.0 SE model: fog lights, heated seats, leather, suspension, 17” wh eels (if thats something you like/want), etc. Plus you get to shift more with the 6 speed transmission. 

As for the rust, I don’t care much about that since I use mine daily, so it doesn’t have much time to rust :).

Hope these help somehow … 


Cheers,
Adrian
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Thanks guys for all your comments. Most useful Smile

 

In the end, the model I was looking at was sold ('59 2.0 SE with 59,000 miles & FSH for £5,684 which I didn’t think was bad).  

 

Ah well, the search continues!

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Hi Adrian, Nathan,

Looking at the Oct 2005 and May 2007 Mk3 and Nov 2011 Mk3.5 UK brochures for manual 2L sport,

all 6 gears (and reverse) and the diff and tyre sizes are the same. This makes for almost exactly 3000rpm at 70mph and just under 3500 at 80mph in both cars so possibly your early car speedo was out or it had lower profile (40?) tyres Adrian?

The Mk3 engine is 160ps at 6700 and the Mk3.5 is 160ps at 7000.

PM me your address if the brochures would help Nathan.

 

 

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The other improvement not mentioned is to the DSC system which was too aggressive on the mk3, the NC3 seems perfect, I have not even seen it flicker on yet.

Must try harder :slight_smile:

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Just to clarify. Am I right in thinking that the NC is the Mk3. The NC2 is Mk3.5 . and the NC3 is the Mk3.75 ?
Can someone confirm or otherwise please.
Gales

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This is all very helpful as I am looking for a Mk 3 now.  My beloved Mk1 has fallen prey to the dreaded rust and won’t get through another MOT without a lot of money spending on it.  I can’t complain as I’ve had the car for 12 years and driven it to work every day.  I had a rush of blood to the head a few months ago and nearly bought a sensible Toyota.  Fortunately I came to my senses in time (on the way to test drive the Toyota) and realised that I really wanted another MX5.  I tested the Toyota, made my polite excuses to the saleslady and left, sinking thankfully into my rusty MK1.

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I haven’t noticed much of a difference between the TC/DSC on the 3 and the 3.5.    They certainly didn’t fixed the quirk that makes the warning light flash after the DSC has done its job.   Admittedly, I haven’t driven a 3.75 yet.

 

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Correct and is my preferred nomenclature, Mk3.75 just sounds ridiculous.

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Hi Rich, 

very good points. Tough the information in the brochures and manuals sometimes disagree. For example, in some materials they say the tank volume is 48L in others they say is 50L. I’ve also seen the different numbers for the minimum turning circle 9.4m and 10m. OK, I’m nitpicking…

 

You might be right about the gearbox. If I made a mistake, was to quote the numbers for the mk3 from my memory. My mk3 had standard tires 205/45/17 (and I also run it with slightly larger diameter tires) and the speedo was within specs, well was overestimating the speed like all do. So no issues there. 
But do you really turn 3000rpm at 70mph on your mk3? I really remember I was somewhere around 3200 rpm on the mk3 … 

I quickly looked at some of the logs I did with my mk3.5 and indeed the final ratio (the diff) is around 3.727 and the 6th gear seems to be 0.832 as in the brochure. Here are some data I get from my logs:
5th - 3680-3700 rpm  -  112 kph  -  69.6 mph
6th - 3050-3080 rpm  -  112 kph  -  69.6 mph 
Note that this is ECU data, so the speedo will show 4-5% higher speed. Unfortunately, I don’t have the mk3 data anymore, nor access to a mk3 to test it. That would make things a clearer. Apologies if my first statement about the mk3 was wrong. 

 

I didn’t state that the mk3.5 engine has more power. I said it pulls stronger. Peak power numbers are not saying all the story. And the fact that they quote the same power for both models in brochures has more to do with emissions and saved Mazda from re-running EU tests, etc. Is the power curve totally flat between 6700 and 7000 rpm? It doesn’t change to 161ps or 159ps? To me it looks like the way they show the numbers is to show that the redline and the rev limit was increased. 

Also, the US specs for mk3.5 with the same engine is 167ps. Granted, they have different maps/tunes for different states due to emission regulations. But still, the mk3.5 was introduced there with an increase in power. And it is mechanically the same engine as here. So what I’m trying to say is that the specs Mazda put in the brochure are just a guide, probably conservative, and not absolute numbers.

Finally, if you tune both engines you get rather similar results, though most tuners (and customers with remapped engines) quote better numbers for the mk3.5, some are due to higher rev limit for the mk3.5 (but again that shows that the torque is not dropping that much at top to have a flat power curve). 

 

Regarding the DSC, I also find it was less intrusive in the mk3.5, but that has to do with a lot more things, suspension, geometry, how good your diff works, tires, etc. But it was something that I noticed and I was trying to upset the car just to see if it works. But hard to tell if they update the DSC software between versions. 

 

Probably I’m biased in my review, but I really loved my mk3 and I was convinced there is not much difference between the mk3 and mk3.5, but for me all the tiny revisions makes the mk3.5 a more refined car (bar the annoying bluetooth button on the steering wheel which I wish it was mute as before and the rather pointless engine sound induction system on the sport models …). 

And one last thing. I find the cruise control on the mk3.5 a good to have option. I don’t use it that much, but if you do long motorways trips it will be handy. And is not that cheap to add it to a mk3.5.

 

OK, I’m done :).

Adrian

 

 

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Hi Adrian, all,

Yes mine’s fine at motorway speeds and I suspect the brochure will have the correct figures.

It’s a fixed mechanical calculation so I put the data into an online calculator like this one,

http://www.not2fast.com/chassis/speed.shtml

What I did question was why they’d raised the red line without producing any more power? Perhaps it was simply to allow a 0-100kpm time in second gear without a shift into third. It’s interesting to compare the second gear speed at 6700 to that at 7000rpm. It may have been originally set to get a decent 0-60mph before tests standardised (in EU anyway) at 0-100kph (0-62mph). Mazda do now claim 7.6 secs for the later car instead of 7.9 secs and they will have looked for valid ways of making the new car look more attractive. That said, Car and Driver got 6.5 secs out of their original road test car so there wasn’t much wrong with that one!

 

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A bit more, I had a look at 4 UK and 4 USA brochures, 2 of each type Mk3 and Mk3.5 for each country.

All the UK Mk3 and Mk3.5 were the same.

All the USA cars though had lower first 3 gears than the UK cars and ran 4.1 diffs as standard. The USA Mk3.5 then got a higher 6th gear (0.787) as well but still ran the 4.1 diff as standard so I wonder if that’s where the higher 6th gear info comes from. With the 4.1 diff though that would still be lower geared than UK cars with 0.832 and 3.727 diff. The Fuji lsd was an option but it doesn’t say if it was a different ratio.

 

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I believe that the Americans calculate/measure engine power without the accessories connected, whereas we take it without.  So their figure would always be higher than our figure for the same engine, map and fuel.

 

I did some tests on a drag strip in a Mk3 5-speed a couple of years back.  Got some interested results, and learned a few things.  The gear ratios are different, but the principles still apply.

I got much better 0-60 times by shifting into 3rd, even though the 5-speed’s 2nd tops out at 63mph.  Oddly, I found that I could either get an optimal 0-60 or an optimal 1/4 mile time, but not both.  The best I got was about 7.4 seconds, which is better than the claimed figures.  6.5 isn’t realistic in a Mk3, IMHO, unless they’d stripped it of quite a lot of heavy parts.

My guess is that they raised the redline because they could (better crank) and then mapped it to meet emissions targets.